From 161f6af9ce1590aac5640b44a744365ed21feeab Mon Sep 17 00:00:00 2001
From: vbarda <vadym@langchain.dev>
Date: Tue, 12 Nov 2024 15:04:47 -0500
Subject: [PATCH] [rfc] core: make tool_call_id optional

---
 libs/core/langchain_core/messages/tool.py | 4 ++--
 libs/core/langchain_core/tools/base.py    | 3 +++
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/libs/core/langchain_core/messages/tool.py b/libs/core/langchain_core/messages/tool.py
index 653dd838f86..b674665dd54 100644
--- a/libs/core/langchain_core/messages/tool.py
+++ b/libs/core/langchain_core/messages/tool.py
@@ -50,7 +50,7 @@ class ToolMessage(BaseMessage):
     to request multiple tool calls in parallel.
     """  # noqa: E501
 
-    tool_call_id: str
+    tool_call_id: Optional[str] = None
     """Tool call that this message is responding to."""
 
     type: Literal["tool"] = "tool"
@@ -119,7 +119,7 @@ class ToolMessage(BaseMessage):
         else:
             pass
 
-        tool_call_id = values["tool_call_id"]
+        tool_call_id = values.get("tool_call_id")
         if isinstance(tool_call_id, (UUID, int, float)):
             values["tool_call_id"] = str(tool_call_id)
         return values
diff --git a/libs/core/langchain_core/tools/base.py b/libs/core/langchain_core/tools/base.py
index 9782234dfb1..e854b668cde 100644
--- a/libs/core/langchain_core/tools/base.py
+++ b/libs/core/langchain_core/tools/base.py
@@ -892,6 +892,9 @@ def _format_output(
     content: Any, artifact: Any, tool_call_id: Optional[str], name: str, status: str
 ) -> Union[ToolMessage, Any]:
     if tool_call_id:
+        if isinstance(content, ToolMessage):
+            content.tool_call_id = tool_call_id
+            return content
         if not _is_message_content_type(content):
             content = _stringify(content)
         return ToolMessage(